But since there will be times where a nice shiny finish is exactly what a piece will need, I am working on improving my polishing skills. The project presented below is made with 22 gauge red brass.
It seems like a simple enough process. Sand your piece with increasingly finer grits in perpendicular directions until all scratches are gone and then do a final clean and polish. Sounds easy enough, right? Well, give it a try and let me know how you do.
Before you start sanding, you want to make sure that your piece is flat. Do the drop test to see (or hear) if your piece is flat.
Hold the piece on edge on a steel block and let go. If it's flat, you'll hear a "plunk" sound. If it's not perfectly flat, you'll hear more of a "tinkle" sound. If you got a "plunk", you're good to start sanding. If you got the "tinkle", you'll need to make it flat before starting your sanding. But maybe you should go to the bathroom first. ; )
To get your piece flat, give it a good wack with your rubber, nylon, or rawhide mallet. My instructor recommended a rubber mallet with steel shot embedded for a little extra oomph! Do the drop test and see how you did. Flip and repeat until you get the "plunk".
Alrighty then, you have a nice flat piece of metal and are ready to start sanding. Well, almost. Get yourself some good tunes on your tune box that will get you in the groove of some good rhythmic sanding.
One problem I have is keeping a good grip on the piece. If I hold it too close to the edges, I end up sanding my fingers about as much as I do the metal.
Sanded finger. Ouch!
I've tried the green alligator tape and it does seem to help, however, if the tape hits the paper it will come off in little chunks that get on your piece and yunk it up. What I have found works best is to use wet-dry paper and dip my fingers in a little water before holding the piece. Not to much - just enough to get a little damp.
For most applications, you'll start with around a 220 grit paper. My metal was in pretty good shape, so I started at 400. The rule of thumb is that you should step up double in grit with each sanding, but I have 600 grit, not 800. So 600 is the second step. My final is 1200. Then a good wash with some blue dish soap.
Sanded across the piece. Notice there is a scratch that showed up in the lower left corner.
Sanded lengthwise again.
After the wash. (looks like copper because of the lighting in the wash room)
I took it for a spin on my new econo-lathe.
I have tripoli loaded on the right and red rogue on the left.
Viola! Very shiny!
What are your finishing / polishing challenges?
Until next time...shine on!